Free Chemical Process Principles MCQs with Answers
2,710 Chemical Process Principles MCQs from Chemical Engineering, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Last updated
2,710 questions · page 49 of 136
- A. Burning on travelling grate
- B. Burning on firebars
- C. Coke making
- D. All A., B. and C.
Explanation: Caking coal softens and agglomerates on heating, producing a coherent, porous solid called coke.
Correct answer: Coke making- A. Ignition temperature
- B. Coke oven gas yield on carbonisation
- C. Chance of catching fire during storage in open space
- D. Smoking tendency on burning
Explanation: Volatile matter escapes readily on heating, so coal with more volatile matter ignites at a lower temperature.
Correct answer: Ignition temperature- A. Coke
- B. Coal having low fusion point of its ash
- C. Anthracite
- D. Coal having high fusion point of its ash
Explanation: Ash with a low fusion point melts in the producer and forms sticky clinker, obstructing the fuel bed and gas passages.
Correct answer: Coal having low fusion point of its ash- A. Scale losses of the furnace stock
- B. Calorific value of the fuel
- C. Flame temperature
- D. None of these
Explanation: Preheating the combustion air adds sensible heat before burning, so less fuel energy is spent heating cold air.
Correct answer: Flame temperature- A. Lower ignition temperature
- B. Narrower limit of inflammability
- C. Higher calorific value
- D. Lower theoretical flame temperature
Explanation: Blast furnace gas is diluted by large amounts of nitrogen and carbon dioxide and contains less combustible material than coke oven gas.
Correct answer: Lower theoretical flame temperature- A. LPG
- B. Gobar gas
- C. Natural gas
- D. Carburetted water gas
Explanation: LPG is rich in propane and butane, whose higher hydrocarbons release much more heat per normal cubic metre than methane-rich natural gas…
Correct answer: LPG- A. Burn CO to CO2
- B. Have proper combustion by supplying it around the burner
- C. Dry and transport the coal
- D. Preheat the tertiary air used for complete combustion of CO to CO2
Explanation: Primary air is mixed with pulverised coal before or at the burner and serves to dry and carry the fine coal into the furnace.
Correct answer: Dry and transport the coal- A. Reduction in coal size
- B. Increase in its friability
- C. Decrease in its caking capacity
- D. All A., B. and C.
Explanation: Weathering weakens coal physically, making it break into smaller particles and increasing its friability.
Correct answer: All A., B. and C.- A. Four
- B. Five
- C. Six
- D. Two
Explanation: Stopes classified coal into four macroscopic constituents: vitrain, clarain, durain and fusain.
Correct answer: Four- A. Bituminous coal
- B. Coke
- C. Semi-bituminous coal
- D. Anthracite
Explanation: Coke is produced by removing most volatile matter from coal, leaving mainly fixed carbon, so it is difficult to ignite.
Correct answer: Coke- A. Durain
- B. Clarain
- C. Vitrain
- D. Fussain
Explanation: Vitrain forms the bright, glassy and lustrous black bands in bituminous coal.
Correct answer: Vitrain- A. Decreases the dew point
- B. Increases the dew point
- C. Reduces the combustion efficiency by limiting the permissible temperature reduction
- D. Both B. and C.
Explanation: Sulphur burns mainly to sulphur dioxide, which can oxidise further to sulphur trioxide and form sulphuric acid vapour.
Correct answer: Both B. and C.- A. May damage its walls due to abrupt excessive swelling of coal
- B. Produces larger size coke
- C. Increases the time of carbonisation
- D. None of these
Explanation: Rapid heating causes coal to swell abruptly while it is being carbonised, producing severe thermal and mechanical stress on the oven…
Correct answer: May damage its walls due to abrupt excessive swelling of coal- A. CA. Provides better control of furnace temperature
- B. All A., B. & C.
- C. Provides higher thermal efficiency & flame temperature
- D. Facilitates combustion with lower excess air
Explanation: Pulverising coal increases its surface area and gives more uniform mixing with air, allowing better temperature control and combustion…
Correct answer: All A., B. & C.- A. Attainment of high temperature
- B. Attainment of chemical equilibrium
- C. Its thorough mixing with air
- D. None of these
Explanation: Some excess air is supplied because real fuel and air do not mix perfectly, so extra air improves contact between oxygen and fuel and…
Correct answer: Its thorough mixing with air- A. 70
- B. 85
- C. 105
- D. 145
Explanation: Furnace oil must be heated substantially because its viscosity falls as temperature rises, improving atomisation at the burner.
Correct answer: 105- A. CH4
- B. CO2
- C. H2
- D. NH3
Explanation: Methane and other hydrocarbons produce glowing carbon particles in the flame, giving coke oven gas its yellowish luminosity.
Correct answer: CH4- A. Increase in gas pressure
- B. Increase in temperature (i.e. preheating)
- C. All A., B. & C.
- D. Use of pure oxygen for combustion instead of air
Explanation: Higher pressure, preheating, and replacing air with oxygen generally make ignition easier and extend the lower and upper flammability…
Correct answer: All A., B. & C.- A. Cyclone separator
- B. Wet packed scrubber
- C. Washing with monoethanolamine
- D. Electrostatic precipitator
Explanation: An electrostatic precipitator effectively removes fine tar fog droplets from coke oven gas by electrically charging and collecting them on…
Correct answer: Electrostatic precipitator- A. Coal
- B. Furnace oil
- C. Natural gas
- D. Naphtha
Explanation: Coal has a high carbon content and relatively little hydrogen, giving it the greatest carbon-to-hydrogen ratio among the listed fuels.
Correct answer: Coal